These noises can result from the passenger seat vibrations preventing the ratchet and the pawl from remaining firmly in contact with one another in the closing position. In particular, the passenger seat vibration can cause oscillations of the ratchet around the closed position. In these oscillations, the ratchet, when set in the closing position, repeatedly moves away from the pawl along a so-called “over-travel” stroke and then periodically hits the pawl, thus producing a rattling contact noise. In order to reduce this noise, it has been proposed to provide the ratchet and the pawl with bumpers which reduce the over-travel of the ratchet. However, the damping properties of these bumpers are heavily affected by variation of temperature and are not constant during the lifecycle of the closure assembly because the elastomeric material of the bumpers has a certain degree of hysteresis.